Abstract: A physiological measurement device or wearable device simulator includes a frame and a plurality of surfaces distributed within the frame. For each surface, a surface actuator links the surface of the frame. At least one of: i) force or position imparted by the surface on a physiological feature of a subject by the surface actuator; and ii) the force imparted by the physiological feature of the subject on the surface, can be employed to modulate the positions of the surfaces relative to each other independently of the forces imparted by or on those surfaces, thereby measuring the physiological feature of the subject or simulating a wearable device interface.

Abstract: In exemplary implementations, a bicycle has “power pedaling”, in which a rider's pedaling efforts are augmented by an electric motor. The rider can control the motor simply by pedaling. It is desirable that the motor torque not exceed the rider torque; otherwise the motor overpowers the rider. A radial flexure is part of the drivetrain that transmits torque from the rider to the back wheel. One part of the flexure is connected to the back wheel casing; another part of the flexure is connected to the freewheel. If motor velocity exceeds rider velocity, this causes the flexure to elastically deform. Two sensors measure the deformation, which is equal to the difference between the angular displacements of the casing and freewheel, respectively. A PD controller seeks to make this difference equal to zero, by controlling voltage levels in the motor (and thus controlling the torque contributed by the motor).

Abstract: In exemplary implementations, a bicycle has “power pedaling”, in which a rider's pedaling efforts are augmented by an electric motor. The rider can control the motor simply by pedaling. It is desirable that the motor torque not exceed the rider torque; otherwise the motor overpowers the rider. A radial flexure is part of the drivetrain that transmits torque from the rider to the back wheel. One part of the flexure is connected to the back wheel casing; another part of the flexure is connected to the freewheel. If motor velocity exceeds rider velocity, this causes the flexure to elastically deform. Two sensors measure the deformation, which is equal to the difference between the angular displacements of the casing and freewheel, respectively. A PD controller seeks to make this difference equal to zero, by controlling voltage levels in the motor (and thus controlling the torque contributed by the motor).